An example telemetry signal detection apparatus may include a optical splitter, a light source optically coupled to the optical splitter, and a light detector optically coupled to the optical splitter. The apparatus further may include a reference loop optically coupled to the optical splitter and a sensor loop optically coupled to the reference loop and the optical splitter. The reference loop may be contained within a reference loop enclosure. The sensor loop and reference loop may comprise a zero-area Sagnac loop with folded optical fiber or dual fiber cable configurations.

An apparatus for acquiring seismic wave data includes a network of geophones and a seismic wave data receiving device coupled to the network and configured to receive the seismic wave data as an optical signal and process the seismic data in real time to provide locations and corresponding sizes of fractures in an earth formation. The network of geophones includes: a plurality of geophone channels, each channel having an array of geophones coupled to a field digitizer unit; an array of geophone patches having geophone channels connected in series by a metallic conductor; a plurality of geophone branches having a metallic conductor and a branch digitizer unit to connect geophone patches in series; a plurality of electrical to optical signal converters for converting signals received from branch digitizer units for transmission using an optical fiber; and a plurality of optical fiber segments for transmitting optical signals to the receiving device.

A method of distributed acoustic sensing includes providing a fiber optic distributed acoustic sensing system having a cable. A straight optical fiber extends parallel to a longitudinal axis of the cable along the cable length. A helically wrapped optical fiber extends along the cable length. The method includes transmitting optical signals into and receiving backscattered signals out of the optical fibers consisting of a component of said optical signals which component has been backscattered from impurities or inhomogeneities in the optical fibers, observing changes in the backscattered signals caused by axial stretching and compressing of the optical fibers caused by an incident wave, comparing the backscattered signals of the straight optical fiber and the helically wrapped fiber, and determining, based on the comparing of the backscattered signals, a direction of wave propagation of the incident wave with respect to the fiber axis for detecting broadside waves and axial waves distinguishably.

A method for acoustic geosteering in directional drilling is provided. The method includes measuring a response from a fiber-optic distributed acoustic sensor disposed on a bottom hole assembly and determining a location of the bottom hole assembly from seismic waves received from surface sources. A subterranean layer structure proximate to the bottom hole assembly is determined from reflections of a locally generated soundwave. Adjustments to geosteering vectors for the bottom hole assembly are determined based, at least in part, on the location and the subterranean layer structure.

A distributed acoustic sensing cable package having a polymer composite extruded over an optical waveguide to encase the waveguide and to form a crystalline matrix layer acoustically coupled to the waveguide. The crystalline matrix includes reinforcement fibers to further enhance transmission of a cable strain to the optical waveguide. During manufacture of the cable, the polymer composite may be extruded over the optical waveguide and subsequently subjected to heat treatment to increase the crystallinity of the polymer composite and increase the elastic modulus. Both axial and radial strain fields are effectively interact with cased fiber waveguide for producing measurable phase shift signal for distributed acoustic noise detection.

A distributed acoustic sensing cable package having a polymer composite extruded over an optical waveguide to encase the waveguide and to form a crystalline matrix layer acoustically coupled to the waveguide. The crystalline matrix includes reinforcement fibers to further enhance transmission of a cable strain to the optical waveguide. During manufacture of the cable, the polymer composite may be extruded over the optical waveguide and subsequently subjected to heat treatment to increase the crystallinity of the polymer composite and increase the elastic modulus. Both axial and radial strain fields are effectively interact with cased fiber waveguide for producing measurable phase shift signal for distributed acoustic noise detection.

A method of monitoring hydraulic fracturing using DAS sensors in a treatment well and/or observation well is described. The raw data is transformed using a low pass filter (≦0.05 Hz) and down-sampled to show the signal as the stimulation progresses. The resulting data can be used to optimize the hydraulic fracturing or improve reservoir models for other reservoirs.

The application describes methods and apparatus for seismic monitoring using fiber optic distributed acoustic sensing (DAS). The method involves interrogating a first optical fiber (102) deployed in an area of interest to provide a distributed acoustic sensor comprising a plurality of longitudinal sensing portions of fiber and also monitoring at least one geophone (107) deployed in the area of interest. The signal from the at least one geophone is analyzed to detect an event of interest (105). If an event of interest is detected the data from the distributed acoustic sensor acquired during said event of interest is recorded. The geophone may be co-located with part of the sensing fiber and in some embodiments may be integrated (307) with the sensing fiber.

Strain and time-strain measurement in a well enables derivation of a constant that links the two. Knowledge of the constant along with time-strain measurement at another well enables estimation of strain at the other well.

A fracturing treatment optimization system using multi-point pressure sensitive fiber optic cables to measure interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data from multiple locations along a wellbore. The fracturing treatment optimization system may analyze the interwell fluid interaction data, microdeformation strain data, microseismic data, distributed temperature data, distributed acoustic data, and distributed strain data, modify a subsurface fracture network model, and calculate interwell fluid interaction effects. The fracturing treatment optimization system may use the fracture network model to measure current and predict future fracture growth, hydraulic pressure, poroelastic pressure, strain, stress, and related completion effects. The fracturing treatment optimization system may enable real-time monitoring and analysis of treatment and monitoring wells. The fracturing treatment optimization system may suggest and effect modifications to optimize treatment of the treatment and monitoring wells.